Lecture Notes in Electrical Engineering 680

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Lecture Notes in Electrical Engineering 680

Zhongliang Jing

Xingqun Zhan Editors

Proceedings

of the International

Conference

on Aerospace

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Lecture Notes in Electrical Engineering

Volume 680

Series Editors

Leopoldo Angrisani, Department of Electrical and Information Technologies Engineering, University of Napoli Federico II, Naples, Italy

Marco Arteaga, Departament de Control y Robótica, Universidad Nacional Autónoma de México, Coyoacán, Mexico

Bijaya Ketan Panigrahi, Electrical Engineering, Indian Institute of Technology Delhi, New Delhi, Delhi, India Samarjit Chakraborty, Fakultät für Elektrotechnik und Informationstechnik, TU München, Munich, Germany Jiming Chen, Zhejiang University, Hangzhou, Zhejiang, China

Shanben Chen, Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, China Tan Kay Chen, Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore

Rüdiger Dillmann, Humanoids and Intelligent Systems Laboratory, Karlsruhe Institute for Technology, Karlsruhe, Germany

Haibin Duan, Beijing University of Aeronautics and Astronautics, Beijing, China Gianluigi Ferrari, Università di Parma, Parma, Italy

Manuel Ferre, Centre for Automation and Robotics CAR (UPM-CSIC), Universidad Politécnica de Madrid, Madrid, Spain

Sandra Hirche, Department of Electrical Engineering and Information Science, Technische Universität München, Munich, Germany

Faryar Jabbari, Department of Mechanical and Aerospace Engineering, University of California, Irvine, CA, USA

Limin Jia, State Key Laboratory of Rail Traffic Control and Safety, Beijing Jiaotong University, Beijing, China Janusz Kacprzyk, Systems Research Institute, Polish Academy of Sciences, Warsaw, Poland

Alaa Khamis, German University in Egypt El Tagamoa El Khames, New Cairo City, Egypt Torsten Kroeger, Stanford University, Stanford, CA, USA

Qilian Liang, Department of Electrical Engineering, University of Texas at Arlington, Arlington, TX, USA Ferran Martín, Departament d’Enginyeria Electrònica, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain

Tan Cher Ming, College of Engineering, Nanyang Technological University, Singapore, Singapore Wolfgang Minker, Institute of Information Technology, University of Ulm, Ulm, Germany Pradeep Misra, Department of Electrical Engineering, Wright State University, Dayton, OH, USA Sebastian Möller, Quality and Usability Laboratory, TU Berlin, Berlin, Germany

Subhas Mukhopadhyay, School of Engineering & Advanced Technology, Massey University, Palmerston North, Manawatu-Wanganui, New Zealand

Cun-Zheng Ning, Electrical Engineering, Arizona State University, Tempe, AZ, USA Toyoaki Nishida, Graduate School of Informatics, Kyoto University, Kyoto, Japan

Federica Pascucci, Dipartimento di Ingegneria, Università degli Studi “Roma Tre”, Rome, Italy

Yong Qin, State Key Laboratory of Rail Traffic Control and Safety, Beijing Jiaotong University, Beijing, China Gan Woon Seng, School of Electrical & Electronic Engineering, Nanyang Technological University, Singapore, Singapore

Joachim Speidel, Institute of Telecommunications, Universität Stuttgart, Stuttgart, Germany Germano Veiga, Campus da FEUP, INESC Porto, Porto, Portugal

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The book series Lecture Notes in Electrical Engineering (LNEE) publishes the latest developments in Electrical Engineering - quickly, informally and in high quality. While original research reported in proceedings and monographs has traditionally formed the core of LNEE, we also encourage authors to submit books devoted to supporting student education and professional training in the various fields and applications areas of electrical engineering. The series cover classical and emerging topics concerning:

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Editors

Zhongliang Jing

Shanghai Jiao Tong University Shanghai, China

Xingqun Zhan

Shanghai Jiao Tong University Shanghai, China

ISSN 1876-1100 ISSN 1876-1119 (electronic)

Lecture Notes in Electrical Engineering

ISBN 978-981-33-6059-4 ISBN 978-981-33-6060-0 (eBook)

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Test Research and Finite Element

Analysis on Extension Performance

of Civil Aircraft Flaps Subjected

to Extreme Temperature

Jingtao Wu, Sibo Zhou, Wenliang Deng, and Yunwen Feng

Abstract Aircraft climate test was conducted to investigate the effect of extreme temperature on extension performance of civil aircraft flaps in aircraft climate labo-ratory. Test results show extending the flaps to 10° requires 9.5 s, 7.8 s, 7.6 s when the standard equipped aircraft was kept at−40 °C, 20 °C and 40 °C for the stip-ulated time, respectively. The lower the temperature is, the more difficult it is to extend the flaps. Furthermore, a finite element analysis (FEA) mode of the flap motion mechanism was proposed to reveal the influence of extreme temperature on deformation and drive torque of the flaps. Actual motion law of flap motion mech-anism was adopted to describe behavior of flap motion mechmech-anism under extreme temperature. The numerical research shows the drive torque decreases from−0.51 × 104_to_{−4.52 × 10}4_{N mm when temperature rises from 20 to 74 °C; conversely}

the drive torque increases from−0.51 × 104_{to 27.5}_{× 10}4_{N mm when temperature}

drops from 2 to−55 °C. In addition, the lower the temperature is, the more obvious the deformation mismatch of the flap mechanism is, which may cause the friction to increase. The increasing friction due to the temperature drop results in the higher drive torque required to extend the flaps, which is also the reason that the time for extending the flaps to 10° increases with the decrease of temperature. The numerical results are observed to mutually agree with the test results mentioned above that the low temperature makes it difficult to extend the flaps.

Keywords Aircraft climate test

·

Standard equipped aircraft

·

Civil aircraft flaps

·

Finite element analysis

·

Extreme temperature

J. Wu (

B

)· S. Zhou · W. Deng

AVIC Aircraft Strength Research Institute, Xi’an, China e-mail:[email protected]

S. Zhou

e-mail:[email protected]

Y. Feng

Northwestern Polytechnical University, Xi’an, China e-mail:[email protected]

System Science and Engineering 2020, Lecture Notes in Electrical Engineering 680, https://doi.org/10.1007/978-981-33-6060-0_1

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2 J. Wu et al.

1 Introduction

The performance of the wing should be considered during cruise, landing and takeoff periods. Therefore, high-lift devices must be used on the original surface of the wing. A typical cross section of the wing is shown in Fig.1[1], in which the flaps exist. During the cruise, the flaps retract to reduce the drag of the aircraft. The flap extension increases the camber and the area of the wing to improve the lift coefficient, and shorten the distance during take-off and landing periods. Flap motion mechanism consists of a large number of motion pairs. It not only needs to bear and transfer loads, but also realize the relative movement between the flap and wing [2–4].

For the flap motion mechanism, it inevitably suffers all kinds of damages during life time, such as load parameters, extreme climate, dimensional error and abrasive wear. Some of the factors give rise to failure of movement mechanism [5–9]. The performance of flaps influences the reliability and safety of an aircraft directly during cruise, landing and takeoff periods. Once its movement mechanism fails and the flap can’t deploy or retract, the aerodynamic performance will be greatly affected [10,11]. Even worse, the Even worse, the deployment or retraction of flap fails, leading to a crash of an aircraft. According to the statistics of aviation accidents, accidents caused by damage of flap motion mechanism had occurred. As a result, many studies have focused on researches of the reliability of the flap mechanism. High-lift mechanisms were analyzed in combination with test data, mathematic model and simulation tech-nology in recent years. As the occurrence of drive strut rupture is the main failure mode of the flap, Yoshida T. et al. used MSC Adams to establish the parametric model of the high-lift system. Dynamical response were analyzed to facilitate under-standing of the normal case and fault case, after validating the simulation model based on the test data [1,12,13]. With regard to flap fault simulation, Huan Pang et al. builded the rigid and flexible coupling model of the flap mechanism, using the virtual prototyping technology, and analyzed the reliability of flap seizure [6,

14]. Reliability analysises of the flap mechanism were conducted, considering the manufacturing errors, aerodynamic loads, component damage and other factors [6,

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Test Research and Finite Element Analysis on Extension … 3

15,16]. In addition, important sampling method was used to analyze the structure reliability of the flap, taking into considerarion of randomness of the elastic modulus, shear modulus and aerodynamic loads [17].

Under extreme temperature, the components of the flap motion mechanism may produce a certain amount of deformation. If the deformation amount is too large, the movement of relevant components may not be in place, which will affect the flap extension performance. In serious cases, it will also cause flaps to jam, which has a great impact on the flight safety of civil aircraft. The damage of flap motion mechanism has caused several accidents. However, the effects of extreme temper-ature on extension performance of civil aircraft flaps have not been globally and adequately researched. In order to reduce the risk and analyze the failure mechanism and reliability of the flap mechanism clearly, in this paper, a finite element anal-ysis (FEA) mode of the flap motion mechanism was proposed to reveal influence of extreme temperature on extension performance of civil aircraft flaps. After vali-dating the simulation model based on the test data, deformation, friction torque and drive torque of the flaps are fully analyzed at extreme temperature. Then, aircraft climate test was conducted to investigate effect of extreme temperature on exten-sion performance of civil aircraft flaps in aircraft climate laboratory. The calculated performance simulation data were compared with the experimental data.

2 Simulation Model Building of the Flap

The finite model of the flap mechanism is comprised of the flap structure, rocker arm, rotation and slide rail mechanism. A typical flap motion mechanism is shown in Fig.2. The coordinate system assembly method is used to establish the motion pairs between the components according to the motion relationship and the corresponding friction coefficient was set at the motion pairs. Load and drive are added to the model to complete the multi-rigid body modeling. Based on the simulation model, the influence of extreme temperature on deformation and extension performance of the flap is analyzed.

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4 J. Wu et al.

3 Change Law of Rotation Angle of Rocker Arm with Time

The extreme temperature influences the extension performance of the flap motion mechanism, so it is necessary to analyze the influence of the extreme temperature on the drive torque. In the model, the temperature affects the magnitude of the friction torque by changing the friction coefficient, which in turn affects the drive torque. Method for calculating the law of rotation angle of rocker arm with time is showed in Fig. 3. Mr, Md, Mg and Mf are the resultent torque, drive torque,

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gravity torque and friction torque of the rocker arm shaft during the extension of flap motion mechanism, respectively. J is moment of inertia of flap motion mechanism. ε represents the angular acceleration of flap motion mechanism. Time required to rotate the same angle in simulation analysis and test is tf and tt, respectively.

The resultant torque is obtained by the following formula:

Mr = Md+ Mg− Mf (1)

The angular acceleration is calculated by the following formula: ε = Mr

J (2)

The variation law of angular acceleration can be obtained through simulation analysis. The variation law of angular acceleration is taken as the input of simulation. Furthermore, through the comparison test and simulation analysis, the error between the simulation analysis and test results is expressed:

δ = tf − tt tt

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if the error does not exceed 15%. Simulation stop is generated.

4 Deformation Analysis of Flap Motion Mechanism

at Extreme Temperature

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6 J. Wu et al.

Fig. 4 Variation of maximum deformation with the rotation angle

In recent years, failure modes of flap motion mechanism have been investigated. As can be seen obviously in Fig.5, the bending and rupture of connecting rod occur. The thermal deformation on the flap motion mechanism will aggravate the wear and stagnation of the flap motion mechanism, resulting in larger drive torque to extend the flap. When the driving torque is large enough, the connecting rod bends or breaks.

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The phenomenon agrees very well with the result above that compressive stress along the connecting rod leads to the bending and rupture of connecting rod.

5 Extension Performance Analysis of Flap Motion

Mechanism

The drive shaft is subjected to drive torque, gravity torque and friction torque during the extension of the flap motion mechanism. Herein, the changes of the driving torque, gravity torque and friction torque at the drive shaft of the flap motion mechanism at 20 °C (room temperature),−55 °C (low temperature) and 74 °C (high temperature) can be obtained through simulation analysis, respectively.

5.1 Extension Performance Analysis at Room Temperature

The evolution of the gravity moment during the extension of the flap motion mecha-nism is shown in Fig.6a. Gravity moment increases with the extension angle. During the extension of the flap motion mechanism, the distance from the center of mass of flap motion mechanism to the drive shaft gets increased, which in turn causes the gravity moment to increase continuously with the extension angle. As also can be found in Figs. 6a,7a and8a, temperature has no effect on the moment of gravity. The value of gravity moment only depends on the distance from the center of mass of flap motion mechanism to the drive shaft.

Figure6b presents the change of the friction torque during the extension of the flap motion mechanism. The friction torque increases rapidly when the flap starts to extend, then becomes almost invariant in magnitudes during the extension of the flap motion mechanism. Whereas the friction torque increases as the temperature decreases. The increasing friction coefficient due to the temperature drop results in the higher friction torque.

Figure6c shows the variations of the drive torque during the extension of the flap motion mechanism. The drive torque of the flap motion mechanism decreases first, then increases as the flap extends. During extension performance of civil aircraft flaps the angular acceleration of the flap mechanism increases from 0 to a certain value in a short time. A larger total torque is required to overcome the inertial force when the flaps start to extend. So the drive torque decreases to−0.51 × 104_N.

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8 J. Wu et al.

Fig. 6 Variation of moment with the rotation angle of flap motion mechanism at room temperature: a gravity moment; b friction moment and c drive gravity

5.2 Extension Performance Analysis at High Temperature

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Fig. 7 Variation of moment with the rotation angle of flap motion mechanism at high temperature: a gravity moment; b friction moment and c drive gravity

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10 J. Wu et al.

Fig. 8 Variation of moment with the rotation angle of flap motion mechanism at low temperature: a gravity moment; b friction moment and c drive gravity

5.3 Extension Performance Analysis at Low Temperature

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Consequently, the drive torque needs to decrease to maintain the torque balance of the flap mechanism. As shown in Fig.8a, b, the change trend of gravity moment and friction moment is similar to that at room temperature.

It is manifest in the contrast among Figs. 6c, 7c and8c, that the drive torque decreases from−0.51 × 104_to_{−4.52 × 10}4 _{N mm when temperature rises from}

20 to 74°C; conversely the drive torque increases from −0.51 × 104 _{to 27.5}_×

104 _{N mm when temperature drops from 20 to}_{−55°C. The lower the temperature}

resultes in greater friction, implying the larger drive torque is needed to extend the flaps. It is concluded that the low temperature makes it difficult to extend the flaps. The extreme temperature influence the friction force of each motion pair of flap motion mechanism. Especially, the drive torque of the flap motion mechanism will be affected to some extent by low temperature, which will increase the risk of jamming or even rupture of the motion mechanism.

5.4 Test Verification of Flap Motion Mechanism Simulation

Model

Aircraft climate test was conducted to investigate the effect of extreme temperature on extension performance of civil aircraft flaps in aircraft climate laboratory. The tests were performed with the non-contact measurement under the stated test conditions. The time for extending the flaps to 10° is used to characterize difficulty of starting to extend the flaps. Test results show extending the flaps to 10° requires 9.5 s, 7.8 s, 7.6 s when the standard equipped aircraft was kept at−40°C, 20°C and 40°C for the stipulated time, respectively. The lower the temperature is, the more difficult it is to extend the flaps.

The numerical results are observed to mutually agree with the test results mentioned above that the low temperature makes it difficult to extend the flaps. The larger drive torque is needed to extend the flaps when temperature decreases. It demonstrates accuracy of the method proposed in the paper.

6 Conclusions

The present study focuses on deformation analysis and effect of extreme temperature on extension performance of civil aircraft flaps. What’s more, drive torque, gravity torque and friction torque are fully analyzed when the flap motion mechanism is subjected to extreme temperature, and simulation model is validated by test. The major conclusions are summarized as follows:

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12 J. Wu et al.

(2) The deformation misfit of flap motion mechanism will aggravate the wear and stagnation of the flap motion mechanism, resulting in larger drive torque to extend the flap.

(3) The increasing friction due to the temperature drop results in the higher drive torque required to extend the flaps. What’s more, negative value of drive torque is converted to positive value due to the decrease of temperature.

Acknowledgements The authors gratefully acknowledge the support for this work from civil

aircraft environmental adaptability research team.

References

1. Heyden T Elastic multibody models of transport aircraft high-lift mechanisms. J Aircraft 46(5):1513–1524

2. Chunlin G et al (2018) Numerical investigation of the effects of different parameters on the thrust performance of three dimensional flapping wings. Aerospace Sci Technol

3. Song Q (2017) Analysis of flap mechanism reliability. In: International conference on mechatronics engineering & information technology

4. Renukumar B et al Effect of flap and slat riggings on 2-D high-lift aerodynamics. J Aircraft. 43(5):1259–1271

5. Cui L, Lu Z, Hao W Importance analysis of the aircraft flap mechanism movement failure. J Aircraft 48(2):606–611

6. Pang H et al (2011) Reliability analysis of the flap mechanism with multi-pivots. Inf Japan 15(12)

7. Rehwald S (2007) Analysis of the performance potential of a single aisle transport aircraft with a new high-lift differential flap system. J Ethnic Migration Stud 33(6):1003–1016

8. Song B (2011) Reliability analysis of the flap mechanism with multi-pivots. In: International conference on quality

9. Tang Z (2015) Nonprobabilistic reliability analysis for an inside flap of an aircraft. J Aircraft 49(1):250–256

10. Liu P (2017) Aerodynamic optimization and mechanism design of flexible variable camber trailing-edge flap.中国航空学报(英文版) 30(3):988–1003

11. Yang L Reliability analysis of structure and control mechanism of aircraft flap. Comput Struct 38(1):21–24

12. Winter E, Woernle C (2013) Multibody modelling of high-lift mechanisms of modern transport aircraft. In: Mechanisms and machine science

13. Yoshida T, Mizusaki Y, Taki T (2004) Analysis and rig test in EMB170 flap mechanism development. In: 24th international congress of the aeronautical sciences (ICAS), pp 1–4 14. Cui L et al (2009) Dynamic response reliability analysis of airplane inner-flap mechanism.

Gaojishu Tongxin/Chin High Technol Lett 19(12):1299–1304

15. Luo X et al (2020) The feasibility and survival mechanism of a large free flap supported by a novel hybrid perfusion mode. Oral Oncol 101:104506

16. Song B (2011) Reliability analysis of the flap mechanism with multi-pivots. Inf Japan 15(12) 17. Tang HM et al (2012) Expression of NPY and 5-HT in rat model of diarrhea-predominant

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Mathematical Modeling

of an Environment Control System

in the Framework of Creating

a Comprehensive Mathematical Model

of Aircraft On-Board Systems

R. S. Savelev, K. S. Napreenko, and A. V. Lamtyugina

Abstract The development and creation of modern aircraft is a complex technical process consisting of many iterations. Successful design and further operation of the developed aircraft models can be achieved only if there is the required amount of research at the design stage and when carrying out the full volume of tests. Also, when developing aviation technology, it is necessary to apply an integrated approach, for example, it is necessary to consider aircraft systems as a complex of interconnected systems, and not as separate, unrelated components. When developing technically complex aircraft systems, it is advisable to use mathematical modeling methods. The main aircraft systems of interest from the point of view of mathematical modeling (determination of the mutual influence of systems, maximum energy loads, opti-mization of aggregate parameters, etc.) and the formation of a complex of interre-lated mathematical models are the following systems: power supply system (PSS), hydraulic system (HS); environment control system (ECS) and fuel system (FS). The study of the joint operation of these systems will allow not only an assess-ment of the parameters of the units and components of the systems, but also an assessment of the operation of the systems as a whole at various operating modes of the aircraft; working out the basic algorithms for controlling systems under various airplane operating modes, to determine the effect of failures of one system on the operation of other systems. In this paper, we consider in more detail the mathemat-ical model of ECS. The main simulated characteristics in the mathematmathemat-ical model of ECS are: change in pressure and temperature in the system through pipelines and on key units (heat exchangers, turbomachine, shutters, etc.); changing the bleed air flow rate in bleed system in case of various operation mods, as well as at different values of the supported pressure in the cabin; change in air flow in the branches of the pipelines of the system with a mixture of hot air in accordance with the algorithms of operation of the valves, etc. A mathematical model of the key node of ECS—an air-cooling unit—is considered, simulation results for various operating modes are shown (airplane parking on the ground on a hot day, flying near the ground and flying at altitude). The developed mathematical model of ECS allows to use it both

R. S. Savelev (

B

)· K. S. Napreenko · A. V. Lamtyugina

Moscow Aviation Institute (National Research University), Moscow, Russia e-mail:[email protected]

System Science and Engineering 2020, Lecture Notes in Electrical Engineering 680, https://doi.org/10.1007/978-981-33-6060-0_2

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14 R. S. Savelev et al.

for evaluating the operation of nodes and units of the ECS, and for use as part of a set of interconnected mathematical models of the aircraft.

Keywords Mathematical model

·

Complex on-board systems

·

Environment control system

·

Heat exchanger

·

Turbomachine

1 Introduction

The development and creation of modern aircraft is a complex technical process consisting of many iterations. Successful design and further operation of the devel-oped aircraft models can be achieved only if there is the required amount of research at the design stage and when carrying out the full volume of tests. Also, when developing aviation technology, it is necessary to apply an integrated approach, for example, it is necessary to consider aircraft systems as a complex of interconnected systems, and not as separate, unrelated components.

When developing technically complex aircraft systems, it is advisable to use mathematical modeling methods. The main aircraft systems of interest from the point of view of mathematical modeling (determination of the mutual influence of systems, maximum energy loads, optimization of aggregate parameters, etc.) and the formation of a complex of interrelated mathematical models are the following systems: power supply system (PSS), hydraulic system (HS); environment control system (ECS) and fuel system (FS).

Mathematical modeling is a relatively new and rapidly developing method for studying the behavior of complex systems [1–5].

The use of mathematical modeling for the design of aircraft systems allows to: – Reduce system design time;

– Optimize the system architecture according to the criteria of weight and energy perfection;

– Create requirements for suppliers of nodes and aggregates; – Develop and optimize control algorithms for onboard systems; – Evaluate the reliability of onboard systems, fault safety.

2 Building a Mathematical Model of a Technical Object

Consider the sequence and relations of stages of building a mathematical model of an object. Figure1shows a flowchart for creating a mathematical model of a technical system.

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Mathematical Modeling of an Environment Control System … 15

Fig. 1 Sequence and

relations of stages of building a mathematical model of an object

The conceptual model formulates the properties of an object that are of interest for building a mathematical model, for example, thermal and gas-dynamic processes that occur during the operation of objects.

The stage of building a mathematical model consists in forming a complex of mathematical dependencies that describe the functioning of the object in general. These dependencies are formed in general terms and contain a complex of values (coefficients) that are not defined at this stage.

The stage of solving the equations of a mathematical model involves determining the coefficients of the equations for a specific type of product and allows to calculate the output parameters or product characteristics that are of interest to us at known values of the input parameters.

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3 Creating a Comprehensive Mathematical Model

of Aircraft On-Board Systems

When developing aviation technology, it is necessary to apply an integrated approach, for example, aircraft systems should be considered as a complex of interconnected systems, and not as separate, unrelated components. Therefore, a promising direc-tion in the development of aircrafts is currently the creadirec-tion of a complex mathemat-ical model of onboard systems. A complex mathematmathemat-ical model of aircraft onboard systems is a combination of all power and mechanical systems that ensure the imple-mentation of the main goals and objectives of the designed aircraft. Figure2shows the structure of a comprehensive mathematical model of on-board systems func-tioning. The structure shows that the aircraft systems are connected to each other by a common connection (electrical energy) through the PSS. PSS is a system that allows to combine several aircraft systems within a complex of interconnected onboard systems [6].

On this structure of the complex mathematical model different types of energy, due to which the interaction of mathematical models of individual systems occurs, are indicated with different colors: red—electrical energy, black—mechanical energy, blue—pneumatic energy, green—hydraulic energy, light green-fuel. The use of the electrical power supply system and electric energy as the basic and unifying system is not accidental. First, it provides operation of aggregates of other systems (power supply of sensors, dampers, shutoff valves, etc.). And also electric energy to date has a number of advantages over other types of energy (for example, in terms of reliability, speed, automation and operation), which has led to the trend of creating aircraft with an increased level of electrification in the aircraft industry [7–10] and replacing traditional types of energy with electric in other areas of industry [11–14]. The main aircraft systems that are of interest for mathematical modeling (deter-mining the mutual influence of systems, maximum energy loads, optimizing

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the parameters of aggregates, etc.) and forming a complex of interconnected mathematical models are the following systems:

– Power supply system; – Hydraulic system;

– Environment control system; – Fuel system.

In addition to these systems, it is also worth noting that to create a digital twin of the aircraft, it is also necessary to consider an inert gas generation system, an anti-icing system, and others.

Research collaboration onboard systems will allow:

– To hold not only the estimation of the parameters of assemblies and units of systems, but also the evaluation of work systems in general in different modes of operation of the developed aircraft;

– Development of the main algorithms for controlling systems in various modes of operation of the aircraft, to determine the impact of failures of one system on the operation of other systems.

4 Mathematical Model of an Environment Control System

When designing and researching environment control system, the method of mathematical modeling is widely used [15–18].

The mathematical model of the ECS contains both the thermohydraulic part (pipelines, heat exchangers, dampers, etc.) and the control system (algorithms of the ECS).

The main input parameters for the mathematical model of the ECS are the charac-teristics of its operating mode (Mach number, height, setting the temperature param-eters in a cockpit, data on cooling electronic units, rates required for other systems (an anti-icing system, an accumulator tank pressurization system-tank pressuriza-tion system, etc.)). The input parameters of the ECS should also include data on the selection from the engine stage (pressure, selection temperature).

The main output parameters of the mathematical model are the parameters of the cooling air (pressure, temperature, flow rate) downstream of the ECS or at the entrance to the air intake sources from the ECS. The output parameters also include sensor signals (temperature, pressure, flow rates, and failure information).

Main modeled characteristics:

– Pressure changes in the system on pipelines and on key units (heat exchangers, turbomachines, dampers, etc.);

– Temperature changes in the system on pipelines and on key units (heat exchangers, turbomachines, dampers, etc.);

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– Change in the air flow rate in the branches of the system pipelines when mixing hot air in accordance with the algorithms of the dampers, etc.

The key node of the system is the air cooling unit (ACU), which includes heat exchangers, turbomachines and other units.

The basic equation for calculating heat exchange effectiveness is Eq.1: εstead y =

φstead y

_C_min_{· (Thot}_,in_{− Tcold}_,in₎ (1) where:

εsteady the effectiveness in steady state,

φsteady the heat exchanged in the heat exchanger in steady state, Cmin the minimal heat capacity rate,

Thot ,in—Tcold ,in the temperature difference between the inlet hot stream and the inlet cold stream of the heat exchanger.

Consider a mathematical model of the environment control system of an advanced aircraft.

Figure3shows a block-scheme of the Environment control system of an advanced passenger aircraft, which consists of two key components—the air bleed system (ABS) and the air cooling unit, as well as pipelines, etc.

The main elements of the air bleed system from the power plant are a pre-heat exchanger; a pressure regulator; a shutoff valve that provides air bleed from a higher or lower engine stage; sensors, control system, etc. The air cooling unit consists of a primary heat exchanger, a secondary heat exchanger, a condenser heat exchanger, a reheater heat exchanger, an air dryer, a three-wheeled turbomachine, sensors, regulating dampers, and control system.

In the Simcenter Amesim software package, the ECS was simulated in various operating modes. One of the key advantages of the developed ECS model is the ability to dynamically model the behavior of the system in the event of various failures in the selection system, which are the most critical in terms of ensuring the normalized air parameters in the passenger compartment. The model calculates the amplitudes of changes in air parameters in the bleed system, as well as the duration of the transition mode, in which there may be no air flow rate in the failed subsystem.

Figure 4 shows how the system works in a failure situation according to the following scenario:

Step 1-Failure of the pressure regulator in one of the two air bleed systems (ABS). Step 2-Opening the cross-selection tap, air supply to the two subsystems from the same engine.

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Fig. 3 Block-scheme of the ECS

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Fig. 5 The temperature at the inlet and the outlet of the turbine

cross-selection tap is opened and two air cooling units are powered from one of the ABS. The graphs (Fig.4) on the left show the pressure and flow rate in the ACU for one side, and on the right the same parameters for the side where the ACU failure occurred. The mathematical model allows to evaluate not only the nature of changes in the parameters under study, but also to numerically estimate the values during transients.

The operation of the ECS on the ground, which ensures that there is no icing at the exit of the turbine due to the mixing of hot air, was also modeled. Thus, using a mathematical model, you can create a control law and select its parameters for the correct operation of the system.

The characteristics of the external environment correspond to the mode of Parking the aircraft in the parking on a hot day (Fig.5).

It is worth noting that the correspondence of the mathematical model to the real object and, as a result, obtaining correct results in the study of various modes of oper-ation of the system is possible only when filling and refining the model with a suffi-cient amount of initial data, which include local pipeline resistances, characteristics of aggregates, operating conditions, etc.

The developed mathematical model of the environment control system (as well as other onboard systems) and the entire complex of onboard systems can be used at all stages of the product life cycle. For example, the developed mathematical models of onboard systems that are validated based on the results of bench and flight tests can be refined, for example, during the modernization of the aircraft (Fig.6).

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Fig. 6 Example of application of mathematical models of on-board systems at various stages of

the product life cycle

5 Conclusion

As a result of the research, a mathematical model of the environment control system is developed, which allows determining the main parameters of the system. It is also worth noting that the developed model can be used in the future to create a complex mathematical model of the aircraft, adding connections with other systems (for example, PSS) and combining into one thermal model. It can also be used at all stages of the product life cycle, both during testing and when upgrading the system. This approach to the creation of new aircraft models will not only allow us to study the issues of mutual influence of systems on each other, including in the case of failure situations, but will also significantly reduce the costs spent on testing and refining on-board systems.

References

1. Satin A, Savelev R, Smagin D, Napreenko K, Neveshkina A (2019) Application simintech software for optimization fuel system parameters of the perspective helicopter. MATEC Web Conf 304:04016

2. Jian FU, Jean-Charles MARE, Liming YU, Yongling FU (2018) Multi-level virtual prototyping of electromechanical actuation system for more electric aircraft. Chin J Aeronaut 31(5):892– 913.https://doi.org/10.1016/j.cja.2017.12.009

3. Wang H, Shang Y, Jia J, Jiao Z (2016) Simulation and analysis for users flow requirements of aircraft hydraulic system based on AMESim. In: Conference: 2016 IEEE/CSAA international conference on aircraft utility systems (AUS).https://doi.org/10.1109/AUS.2016.7748165

4. Tang J, Liu Q, Hu J, Huo J, Wang L (2018) Leakage fault diagnosis method of aircraft landing gear hydraulic cylinder based on wavelet packet. J Eng.https://doi.org/10.1049/joe.2018.9037

Lecture Notes in Electrical Engineering 680

Lecture Notes in Electrical Engineering 680

Zhongliang Jing

Xingqun Zhan Editors

Proceedings

of the International

Conference

on Aerospace

Lecture Notes in Electrical Engineering

Volume 680

Contents

Test Research and Finite Element

Analysis on Extension Performance

of Civil Aircraft Flaps Subjected

to Extreme Temperature

·

·

·

·

B

1

Introduction

2

Simulation Model Building of the Flap

3

Change Law of Rotation Angle of Rocker Arm with Time

4

Deformation Analysis of Flap Motion Mechanism

at Extreme Temperature

5

Extension Performance Analysis of Flap Motion

Mechanism

5.1

Extension Performance Analysis at Room Temperature

5.2

Extension Performance Analysis at High Temperature

5.3

Extension Performance Analysis at Low Temperature

5.4

Test Verification of Flap Motion Mechanism Simulation

Model

6

Conclusions

References

Mathematical Modeling

of an Environment Control System

in the Framework of Creating

a Comprehensive Mathematical Model

of Aircraft On-Board Systems

B

·

·

·

·

1

Introduction

2

Building a Mathematical Model of a Technical Object

3

Creating a Comprehensive Mathematical Model

of Aircraft On-Board Systems

4

Mathematical Model of an Environment Control System

5

Conclusion

References